000
AXPZ20 KNHC 150242
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU SEP 15 2011

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0245 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM EASTERN PANAMA AT 10N80W TO 
07N89W...THEN TURNS NW TO NEAR 10N100W...CONTINUING W ALONG 10N 
TO A 1010 MB LOW PRESSURE CENTER AT 10N113W...THEN W TO A 
CONVECTIVE FREE 1013 MB LOW PRES AT 14N124W...THEN SW TO NEAR 
12N127W. ITCZ AXIS EXTENDS FROM 12N127W TO BEYOND 10N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITH NUMEROUS 
LIGHTNING STRIKES IS NOTED ALONG THE PACIFIC COASTS OF COLOMBIA 
...PANAMA...NICARAGUA AND EL SALVADOR. SMALL CLUSTERS OF 
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS OBSERVED 
WITHIN 30 NM OF 06N93W...N OF 12N BETWEEN 96W AND 102W...WITHIN 
30 NM EITHER SIDE OF A LINE FROM 06N96W TO 08N104W TO 11N105W 
...AND ALSO WITHIN 30 NM EITHER SIDE OF A LINE FROM 08N132W TO 
09N140W.

..TROPICAL WAVE...

A TROPICAL WAVE EXTENDS FROM 10N TO 15N ALONG 98W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 60 NM EITHER 
SIDE OF A LINE FROM 12N100W TO 17N99W.

AN UPPER CYCLONE IS OVER WESTERN ARIZONA WITH AN UPPER SHORTWAVE 
TROUGH EXTENDING SW FROM 32N117W TO 23N126W TO 20N131W AND INTO 
AN UPPER CYCLONE W OF THE DISCUSSION AREA AT 19N146W. AFTERNOON 
CONVECTION FLARED ALONG THE MEXICAN SIERRA MADRE OCCIDENTAL WITH 
THE DEBRIS MOISTURE IS NOW ADVECTED NE ACROSS NORTHERN OLD 
MEXICO AND W TEXAS. UPPER MOISTURE IS ALSO STREAMING NE OVER 
MOST OF NEW MEXICO.  

AN UPPER ANTICYCLONE IN NOTED W OF THE AREA AT 31N145W WITH A 
RIDGE EXTENDING E INTO THE AREA CRESTING AT 26N130W. ANOTHER 
UPPER ANTICYCLONE IS E OF THE TROUGH...OVER CENTRAL OLD MEXICO 
AT 21N99W...WITH AN UPPER RIDGE EXTENDING SW OVER THE PACIFIC TO 
A CREST AT 15N121W. AN UPPER RIDGE ALSO EXTENDS SE ACROSS 
CENTRAL AMERICA TO A CREST OVER THE HONDURAN AND NICARAGUAN 
BORDER. THIS SETS UP NE FLOW ALOFT ACROSS THE TROPICAL N PACIFIC 
TO THE E OF 100W. CONVECTION FLARED EARLIER OVER SOUTHERN OLD 
MEXICO AND CENTRAL AMERICA WITH THE DEBRIS MOISTURE NOW ADVECTED 
ABOUT 540 NM TO SW OVER THE PACIFIC. ISOLATED CONVECTION WAS 
ENHANCED ALONG THE W PERIPHERY OF THE RIDGE...WITHIN 150 NM OF 
14N118W...AND THE DEBRIS MOISTURE IS NOW MOVING N AND NE ALONG 
THE RIDGE CREST BUT EVAPORATING NEAR 20N114W. THE UPPER LEVELS 
APPEAR VERY DRY N OF 13N W OF 120W...AND N OF 20N BETWEEN 120W 
AND 110W.

AT THE LOW LEVELS HIGH PRESSURE IS CENTERED NW OF THE AREA WITH 
A RIDGE ALONG 32N135W TO 18N113W. A SMALL AREA OF NE TRADES AT 
15 TO 20 KT CONTINUES FROM 11N TO 17N W OF 130W AND EXPECTED TO 
EXPAND E TO ALONG 127W ON THU. 

SOUTHERLY CROSS EQUATORIAL SWELL RESULTING IN COMBINED SEAS TO 8 
FT CONTINUE OVER THE TROPICAL WATERS S OF 08N W OF 110W. 
SOUTHWESTERLY SURFACE WINDS ARE EXPECTED TO INCREASE TO 15 TO 20 
KT...WITH COMBINED SEAS TO 9 FT...IN THE AREA FROM 04N TO 09N 
BETWEEN 97W AND 115W ON THU.   

$$
NELSON